Console object API Reference

Use the console object's methods to write messages to the Console from your JavaScript.

You can also enter these methods into the Console. For example, in the Console, to enter a console method that takes a variable:

1. In the Sources tool, in the Debugger, set a breakpoint in your JavaScript code.

2. In the Debugger, step through your code.

3. When you are in a valid context so that the desired variable is in-scope, enter a method of the console object into the Console tool. The result is displayed in the Console.

---

assert

Writes an error to the Console when expression evaluates to false.

JavaScript

console.assert(expression, object)

Log level: Error

Example

JavaScript

const x = 5;
const y = 3;
const reason = 'x is expected to be less than y';
console.assert(x < y, {x, y, reason});

Output

---

clear

Clears the Console.

If Preserve Log is turned on, the clear method is turned off.

JavaScript

console.clear()

See also

• Clear the Console

---

count

Writes the number of times that the count method has been invoked at the same line and with the same label. Use the countReset method to reset the count.

JavaScript

console.count([label])

Log level: Info

Example

JavaScript

console.count();
console.count('coffee');
console.count();
console.count();

Output

---

countReset

Resets a count.

JavaScript

console.countReset([label])

Example

JavaScript

console.countReset();
console.countReset('coffee');

---

debug

Identical to the log method, except different log level.

JavaScript

console.debug(object [, object, ...])

Log level: Verbose

Example

JavaScript

console.debug('debug');

Output

---

dir

Prints a JSON representation of the specified object.

JavaScript

console.dir(object)

Log level: Info

Example

JavaScript

console.dir(document.head);

Output

---

dirxml

Prints an XML representation of the descendants of node.

JavaScript

console.dirxml(node)

Log level: Info

Example

JavaScript

console.dirxml(document);

Output

---

error

Prints the object to the Console, formats it as an error, and includes a stack trace.

JavaScript

console.error(object [, object, ...])

Log level: Error

Example

JavaScript

console.error("I'm sorry, Dave.  I'm afraid I can't do that.");

Output

---

group

Visually groups messages together until the groupEnd method is used. Use the groupCollapsed method to collapse the group when it initially logs to the Console.

JavaScript

console.group(label)

Example

JavaScript

const label = 'Adolescent Irradiated Espionage Tortoises';
console.group(label);
console.info('Leo');
console.info('Mike');
console.info('Don');
console.info('Raph');
console.groupEnd(label);

Output

---

groupCollapsed

Identical to the log method, except the group is initially collapsed when it logs to the Console.

JavaScript

console.groupCollapsed(label)

---

groupEnd

Stops visually grouping messages. See the group method.

JavaScript

console.groupEnd(label)

---

info

Identical to the log method.

JavaScript

console.info(object [, object, ...])

Log level: Info

Example

JavaScript

console.info('info');

Output

---

log

Prints a message to the Console.

JavaScript

console.log(object [, object, ...])

Log level: Info

Example

JavaScript

console.log('log');

Output

---

table

Logs an array of objects as a table.

JavaScript

console.table(array)

Log level: Info

Example

JavaScript

console.table([
      {
         first: 'René',
         last: 'Magritte',
      },
      {
         first: 'Chaim',
         last: 'Soutine',
         birthday: '18930113',
      },
      {
         first: 'Henri',
         last: 'Matisse',
      }
]);

Output

---

time

Starts a new timer. Use the timeEnd method to stop the timer and print the elapsed time to the Console.

JavaScript

console.time([label])

Example

JavaScript

console.time();
for (var i = 0; i < 100000; i++) {
      let square = i ** 2;
}
console.timeEnd();

Output

---

timeEnd

Stops a timer. For more information, see the time method.

JavaScript

console.timeEnd([label])

Log level: Info

---

trace

Prints a stack trace to the Console.

JavaScript

console.trace()

Log level: Info

Example

JavaScript

const first = () => { second(); };
const second = () => { third(); };
const third = () => { fourth(); };
const fourth = () => { console.trace(); };
first();

Output

---

warn

Prints a warning to the Console.

JavaScript

console.warn(object [, object, ...])

Log level: Warning

Example

JavaScript

console.warn('warn');

Output

---

See also

• MDN Web Docs > console object Reference - Has a summary overview of the methods, and has one page per method, with additional syntax details.
• Log messages in the Console tool - An interactive introduction.
• Console tool utility functions and selectors - Console-only utility methods, such as debug() and monitorEvents().

Nota

Portions of this page are modifications based on work created and shared by Google and used according to terms described in the Creative Commons Attribution 4.0 International License. The original page is found here and is authored by Kayce Basques.

This work is licensed under a Creative Commons Attribution 4.0 International License.